High definition televisions are finally becoming more popular and more available in the United States. Historically, standard definition televisions received the NTSC (National Television Systems Committee) standard transmitted signals. The ATSC Advanced Television Systems Committee) standard has been adopted in the U.S. for terrestrial transmission of HDTV (High Definition Television) signals. The country is currently going through a transition period where both standards are in use.
Retail sales outlets for HDTV televisions want to show the advantages in picture and sound quality that HDTV sets offer over standard definition sets. Prior to the present invention, they have used an analog NTSC signal generator or a local television broadcast to demonstrate the standard definition sets. At the same time, they will use an HDTV player that plays recorded MPEG source material to demonstrate the HDTV sets (many areas don't have HDTV broadcasts yet, and those that do have the HDTV broadcasts only show HDTV during primetime). While this works for showing each type of set, it is difficult for consumers to make a comparison if the differing types of sets have dissimilar video content being shown. Also, during this transition period, retail sales outlets need to have multiple generators to provide signals for the different standards. It would be advantageous to have one source that could provide signals according to both standards to save on cost, space, and operational expenses.
As mentioned previously, whenever an NTSC signal has been needed for any reason—whether demonstration, signage, testing, or other reasons—either an over-the-air signal or an analog generator was used to provide the signal. It is not within the scope of this application to go into detail on how these signals are generated, since the NTSC standard has been around for a long time. But generally, an analog baseband video signal is modulated and up-converted to an RF frequency to feed into a standard NTSC TV.
ATSC signals can sometimes be received over the air, but it is much more consistent, and increasingly more common, to use an HDTV video player with an RF output to produce the ATSC signal needed for demonstration and testing purposes. These video players will generally store MPEG transport streams, serially feed a stream into an 8-VSB modulator, and up-convert it to an RF frequency for an ATSC compatible television to receive, demodulate, decode and display.
It is an object of the invention, generally stated, to produce a singular device that simultaneously produces NTSC and ATSC outputs with the same video and audio content so that the same content can be simultaneously viewed side-by-side on a standard definition NTSC television and an ATSC HDTV set.